Recovery of organic acids from oxidation products of hydrocarbons



Patented Sept. 22, 1936 i 2,055.09; necovuar or one amc sums anon! onDATION raonuc'rs or nvnaocaanons Hans Beller, Ludwigshaien-on-the-Rhine,and

Max Schellmann, Mannheim, Germany, as-

' 2,055,095 FFlC'E signors to I. G. F'arbenindustrie Aktiengesell--schatt, Frankfort-on-the-Main, Germany No Drawing. "Application December12,1934, Serial No. 156,702. In- Germ'any November 7,

- '11 Claims.

I'he present'invention relates to improvements in the recovery oforganic acids irom oxidation products of liquid or solid, non-aromatichydrocarbons, such as scale wax, purifledparaflin wax, paraihn oils, orcrackedfractions of petrolatum. In Patent No. 1,931,859, dated October24th,

c 1933, one of us has described a process for the recovery of organicacids form the oxidation prod-- nets of non-aromatic hydrocarbons, whichis based on thesaponification of the oxidation products with aqueoussolutions of carbonates of the alkali metals 'or alkaline earth metals.It has also been proposed to saponiiy the oxidation products ofnon-aromatic hydrocarbons with oxides or hydroxides of the alkali metalsor alkaline earth metals in order to recover the acid components.

As is known, the oxidation with air or other agentsiyieldixk oxygen,such as nitrogen oxides in the liquid or gaseous phase, yields besidesthe valuable normal carboxylic acids also hydroxy carboxylic acids orderivatives thereof, such as lactones, lactides, estolides, etc., whichcompounds we may designate as super-oxidized components of the oxidationproducts; they injure considerably the duality. of the oxidationproducts.

By means 01! the known saponification methods; these undesirablesuper-oxidized components 80 are obtained together with the carboxylicacids and can be removed therefrom only in a costly and complicatedmanner. The "presence of these components can be recognized by the factthat,"

the carbdxylic acids are not completely soluble 5 in low-boilinghydrocarbons on account of the;

. presence, for'instance, of hydroxy acids, and that the acid-andsaponiflcation numbers of the acid parts which havebeen completely freedfrom unsaponifiable components, show a substantialdii- 40 ierence whichis usually designated as ester number. i Typical carboxylic acidsasobtainable, ior in: stance, by the oxidation of crude scale wax with airin the liquid phase, show an ester num ber oi about 30 to '70 and acontent of acids insoluble in low-boiling hydrocarbons, for instance,petrol ether, of about 5 t o-15 percent; these acids are hydroxy fattyacids. I

We have ow found that fatty acids tree or practidally i ee from the saidundesired component such as hydrozw acids can be obtained from. t eoxidation products of from liquidto solid, non-aromatic i, e. open chainaliphatic or cycloaliphatic hydrocarbons by removing the water duringthe saponiflcation which is-carried out with alkaline reacting agentssuch as, for

instance oxides, hydroxides, or carbonates of alkalior alkalin'e earthmetals. Thus duringthe whole ,saponi'flcation period orat least asubstaniftial part thereof, practically no water is prme'nt.

(01. 260-122) I a I The reaction can be commenced in the presence ofwater, but on reaching higher temperatures,

, great care must be taken that all the water, that is, the water whichmay have been used for dissolving or dispersing the alkaline reactingagent, 5 and the water formed during the saponiflcation reaction, isremoved. Suitable temperatures e those of about 150 C. to about 300 C.For practical reasons one will work at about 280 to 300 0., whereby thereaction is usually. finished in 10 about 1 to 2 hours.

' The presence of inert'gases' doesnot disturbthe reaction; it may evenbe advantageous, yielding lightly colored products. Also, additions canbemade which favor the splitting of! of water or yield-especiallylightly colored products such as,

for instance, aluminum oxide or metal powders of, tor instance, zinc,copper, magnesium or aluminium. I

While it is possible to work under ordinary pressure, reduced pressuremay be applied where- L by the removal of water from the highly heatedsoap is favored. On the other hand it may be of advantage to effectthesaponification under increased pressure. The unsaponiflable parts Ipresent during the saponiflcation 01' the saponi fiable parts actpresumably as solvents or diluent's for the latter andthereby help toavoid -undesired cracking of the soaps at the high temperaturesapplied.- Unsaponiflable matter from an external-smirce may be added tothe material to be saponifled iory the same purpose.

The saponiflcation can be carried out, for instance, with causticalkalies, alkali carbonates, oxideslor hydroxides otthe alkaline earthmetals or with mixtures of these alkaline reacting a'gentswhich may beemployed in dry form or in aqueous solution or suspension, whereby gen-'erally an excess of about 3 to 8 per cent over the .amount orsaponifying agent, theoretically required, is applied; the theoreticalamount isto correspond tothe saponiflcation number otthe respectiveoxidation product. .It may, however,

\ be advantageous to employ lower amounts of the alkaline reactingreagents than the theoretical amount, for example per cent oi thelatter.

Suitably, the reaction is carried throughina closed and heatable vesselprovided with a stirrer, from which vessel the water vapor producedduring the reaction, partly by'the saponiiilcation reaction at to 200?C.', and partly by the splitting oi! or '.water from hydroxy acids orderivatives thereof at 180 to 350 0., is 6ontinuously released. .j'l'hehydronacids are by c this treatment, practically almost completely,trapsior'med into other products, and the ester number of the oxidationproduct is, substantially diminished or evendisappears completely. Instead of continuously releasing the pressure it may be released fromtime to time.

If free acids are to be produced the saponification mixture is acidifiedand the acids are recovered. Otherwise the acids are obtained in theform of their salts.

The following table shows the results which were obtained in thesaponification of the oxidation product of crude scale wax at lowtemperature in the presence of water, at high temperature in thepresence of water and under pressure, and at high temperature in theabsence of water.- These results show clearly that the effect arrived atby saponification at a high temperature in the presence of water isconsiderably improved by working in the absence of water.

especially desirable.

The following examples will further illustrate the nature of the presentinvention but the invention is not restricted to these examples. The

parts are by weight.

Example 1 An oxidation product, obtained by oxidation of crude scale waxwith air at 140 C. in the liquid phase and containing 44 per cent ofunsaponifiable components, is washed with water for the removal ofwater-soluble acids, and thereupon saponified in an autoclave providedwith' astirrer, with an amount of anhydrous caustic soda by 4 per cent.in excess of the amount required for the'complete saponification of thefatty acids and esters, for four hours and at-frocm 290 to 300 C. Aftera temperature of 150 C. had been reached, the water produced by thesapo'nification reaction is removed by releasing, the pressure each timewhen the pressure in the autoclave had risen to about 10 atmospheres.The reaction is brought to a finish without the application ofsuper-atmospheric pressure.

After cooling, the reaction mass is mixed with water and theunsaponifiable parts are removed by extraction with low-boilinghydrocarbons, and from the aqueous solution of the soaps the fatty acidsare liberated by acidification with diluted sulphuric acid. Afterwashing with water,

these acids show the following analytical data:

Acid number .190

Saponification number 199 Ester number 9 Per cent hydroxy acids-.. 0.9

Example 2 An oxidation product from purified scale wax I containing 59per cent of unsaponifiable components and obtained by oxidation with airat 140 C., in the presence of a manganese catalyst, is saponifiedwithdry sodium carbonate in excess, at290-300 C. in an autoclaveprovided with a stirrer, the pressure produced being released in thesame manner as in Example 1.

The reaction is brought to a finish in the absence of water and withoutthe application of superatmospheric pressure.

On application of the working-up method described in Example 1, fattyacids are obtained from the reaction mixture which, after distillation,show the following analytical data:

Acid number- 240 Saponification number 240 Ester number Per cent hydroxyacids 0 Example 3 The oxidation product referred to in Example 1 ismixed with a suspension of calcium hydroxide in 10 times its amount ofwater, calcium hydroxide being employed in an excess of 7.5 per 1 centof the amount theoretically necessary for the complete saponification ofthe fatty acids and esters. The mixture is treated for 2 hours in astirring autoclave at from 290 to 300 C.

The removal of the water added and formed during the saponification iseffected by releasing the pressure after the temperature of 300 C.

has been attained. The saponification is then 1 completed without theapplication of superatmospheric pressure. The saponification productobtained is mechanically disintegrated and heated to boiling with anexcess of an aqueous sodium carbonate solution until the calcium soapsare converted into sodium soaps. After filtering oif the calciumcarbonate precipitated,

the filtrate is worked up in the manner described in Example 1. Thecrude fatty acid mixture thus obtained has the followingcharacteristics:- Acid number 187 Saponiflcation number 200 Ester number13 Per cent hydroxy acids 2.4

This mixture is subjected to a steam-distillation under a pressure offrom 10 to -15 millimeters mercury gauge with a maximum temperature of280 C. The fatty acids thus obtained have the following characteristics:

Acid number 23-6 Saponification number 239 Ester number 3 Per centhydroxy acids 0 The color of the product determined in the 6"-cell ofthe Lovibond-tintometer (compare Holde, Kohlenwasserstoffe, 61c undFrette 7th edition, 1933, pages 233 to 234) is yellow 40 and red-12. 4

Example 4 The oxidation product referred to in Example 1 is saponifiedwith barium hydroxide (Ba (OH) 2.H20)

under otherwise the same conditions as indicated in Example 3. After thesteam-distillation in vacuo a fatty acid mixture is obtained which has.

the following characteristics:

Acid number I 209 Saponification number 211 Ester number -1 e 2 Per centhydroxy acids 0 Color (determined as indicated in Example 3) yellow 35and red 1'7.

Example 5 The oxidation product referred to in Example 2 is treated withanhydrous sodium carbonate (85 per cent of the amount theoretically necusary for the complete saponinca'tion of the fatty acids and esters) for2 hours at about 300 C. in a stirring autoclave, the water formed in thesa-' 5 poniflcation being removed from the reaction mixture bytemporarily releasing the pressure after a temperature of 300 C. hasbeen attained; After working up as described in Example 1 a crude fattyacid mixture is obtained whichha the following characteristics:

Acid number 19'! Saponiflcation number 209 Ester number 12 15 Per centhydroxy acids l 1.9

After steam-distilling the product under the conditions stated inExample 3 a fatty acid mixture is obtained having the followingcharacter istics:

Acid number k i 226 Saponification number 228 Ester I number 2 Per centhydroxy acids 0 Color (determined as indicated in Example yellow 42 andred 7.5.

EzamDleG t The oxidation product referred to Example 2 is treated for 2hours at 300 0. with a -20 icent aqueous solution of sodium carbonatewhich is employed in a 10 per cent excess of the" amount theoreticallynecessary for completely saponifylng 5 the fatty acids and esters. Thesaponincation is carried out under a pressure of from .25 to 40 vmillimeters mercury gauge in a vessel provided with a stirrer and areflux-condenser which is heated with ,steam; The-'non-saponiflablecompounds boiling above 100 C. are thus condensed 40 and flow back intothe reaction vessel while the water added and formed in .thereactiondistils off through the reflux condenser and is collected ina cooledreceptacle. y After working up as described in Example .1

a mixture of fatty acids is obtained which after t steam-distillationunder the conditions of Example 3 has the following properties; Acidnumber I Ester number k i 0 Per cent hydroxy acids 0 Color (determinedas indicated in Example 3) yellow 30 and red 14. j t v 100 parts or theoxidation preduttre'zerred'te. in Example 1 are treatedwith anhydrouscarbonate (10 per cent excess of the amounttheoreticallynecessary forthecompletesarioniflcation of the fatty acidsand esters) with theaddition of parts*of crude paraffin wax at about 300 C. fori2 hours in astirring autoclave. As

soon as the temperature of 300 G isattained the waterformed inthesaponiilcation is removed -byrelease of the pressure andthesaponiflcation is completed under ordinary pressure;

" The crude fatty acid mixture obtained by working up in the mannerdescribed in Example .1 i

70 has the following characteristics:

Acid number e 193 "Saponification number 204 t Ester number 11 16 Percent hydroxy acids;

' working up as vi'ollt'uiviuiz characteristics: t

v m 50 Saponification number 223' The fatty acids obtained in}steam-distillation in vacuo of the said crude mixture have the followingproperties: v

Acid number: 228 Saponiilcation number 228 Ester number 0 Percenthydroxy acids 0 Color-- (determined as yellow 24 :and red 16.

i Example 8 500 parts 8f the oxidation product referred to in Example 1are treated for 2 hours at about indicated. in Example 3) 300 C. in astirring autoclave with an amount .of 15 following characteristics: 254mm number i 184 j Saponification number 199 Ester number 15 Per centhydroxy acids 0.8 so

By subjecting the crud mixture to a steamdistillation in the vacuum asdescribed in Example 3 fatty acids are obtained which possess the' Acidnumber. 245 {86 Saponification number 245 Inter-number; i 0 Per centhydroxy acids 0 Color (determined as indicated in Example 3) i yellowand red 12.-

If'instead of the zinc dust 0.5 part of alumini-,

z um dust is employed a crude fatty acid'mixture of .the followingcharacteristics is obtained:

Acid number i 187 t Saponiflcation number 197 i Ester number 10 Per centhydroxy acids 1.5

1 By steam-distillation in vacuo this product yields afatty acid mixtureof the following char acteristics;

Acid number; 231 S aponiflcation number 235 Ester number 4 Per centhydroxy acids 0 Color (determined as indicated in Example 3) yellow 20andred 10.

If instead of zinc dust 0.5 part of magnesium powder is added -a fattyacid mixture 'is obtained which "has the following characteristics:-.

Aoid number 188 8a 'tion' number 200 Ester number .,I;.. ,121 Percenthydroxy acids 1.8

After distilling the product as indicated above a fatty acid mixture ofthe following charac teristies is obtained. I r

'A'cid number Y 242 Saponiilcation number s 245' Ester number- Per centhydroxy acids 0 Color (determined as indicated in Example 3) yellow 24and red 6.5.

Example 9 500 parts of the oxidation product referred to in Example 1are treated in a stirring autoclave for 2 hours at about 300 C. withsodium hydroxide (40 per cent excess of the amount. theoreticallynecessary for the complete saponification of the fatty .acids andesters) with the addition of 25 parts of titanium dioxide. The waterformed is removed as described in Example 5.

By working up as indicated in Example 1 a crude fatty acid mixture isobtained having the following characteristics:

Acid number 196 Saponification number 206 Ester number 10 Per centhydroxy acids 2.3

After distilling this mixturein the-manner in-' dicated in Example 3 afatty acid mixture of the following characteristics is obtained.

Acid number 227 Saponiflcation number A 232 Ester number .Per centhydroxy acids Color (determined as indicated in Example 3) yellow 40 andred 10.5.

Example 10 kept at 300 C. for 2 hours, after each 30 minutes thepressure being released and fresh hydrogen being pressed in up to apressure of 50 atmospheresm The crude fattyacid mixture obtained afterworking up as described in Example 1 has the following characteristics.

Acid number 169 Saponification number 182 Ester number 13 Per centhydroxy acids 1.7

After distilling this product as described in Example 3 a fatty acidmixture is obtained .which has the following characteristics.

Acid number- 239 Saponification number 243 Ester number. 4 Per centhydroxy acids 0 Color (determined as indicated in Example 3) yellow 30and red 4.5.

What we claim is:

1. A processfor recovering substantially the entire saponifiable part ofan oxidation product, obtainable by the liquid-phase oxidation of fromliquid to solid,-non-aromatic hydrocarbons, in the form of fatty acids,which comprises subjecting the entire oxidation product to asaponiflcation process at temperatures of from about C.

to about 350 C. by means of an alkaline reacting agent selected from thegroup consisting of the oxides, hydroxides and carbonates of the alkalimetals and alkaline earth metals while removin thewater and separatingthe unsaponifiable part of the oxidation product from the saponifiedpart.

2. A process for recovering substantially the entire saponifiable partof an oxidation product, obtainable by the liquid-phase oxidation offrom liquid to solid, non-aromatic hydrocarbons, in the- 3. A processfor recovering fatty acids, which comprises subjecting oxidized materialcomprising the saponifiable part of an oxidation product, obtainable bythe liquid-phase oxidation of from liquid to solid, non-aromatichydrocarbons to a saponification process attemperatures of from about180 C. to about 350 C. by means of an alkaline reacting agent selectedfrom the group consisting of the oxides, hydroxides and carbonates ofthe alkali metals and alkaline earth metals, substantially in theabsence of water and setting free the acids from the latter.

4. A process for recovering substantially the entire saponifiable partof an oxidation product, obtainable by the liquid-phase oxidation offrom liquid to solid, non-aromatic hydrocarbons, in the form of fattyacids, which comprises subjecting the entire oxidation product to asaponification process at temperatures of from about 180 C. to about 350C. by means of an alkaline reacting agent selected from the groupconsisting of the oxides, hydroxides and carbonates of the alkalimetalsand alkaline earth metals, while removing the water, separating theunsaponifiable part of the oxidation product from the saponifietl partand setting free the acids from the latter. i

5. A process for recovering substantially the entire saponifiable partof an oxidation product, obtainable by the liquid-phase oxidationof fromliquid to solid, non-aromatic hydrocarbons, in the form of fatty acids,which comprises subjecting the'entire oxidation product to asaponification process at temperatures of from about 180 C. to

about-350 C. by means of an alkaline reacting agent selected from thegroup consisting of-the oxides, hydroxides and carbonates of the alkalimetals and alkaline earth metals in an amount by about 3 to 8 per centin excess of that corresponding 'to the saponification number of theentire oxidation product, substantially in theabsence of water,separating the unsaponifiable part of the oxidation product from thesaponified part and setting free the acids from the latter.

6. A process for recovering substantially the entire saponifiable .partof an oxidation product, obtainable by the liquid-phase oxid'ation offrom liquid to solid, non-aromatic hydrocarbons, in the form of fattyacids, which comprises subjecting the entire oxidation product in aclosed, pressuretight vessel to a saponification process by means of analkaline reacting agent selected from the group consisting of theoxides, hydroxides and carbonates of the alkaline metals and alkalineremoved from the reaction vessel,

earth metals, substantially in the absence of water, at temperatures offrom about 150 C to about 300' Ct, care being taken that any water vaporproduced by the saponiflcation reaction is finishing the reaction in theabsence of super-atmospheric pressure, separating the unsaponificablepart of the oxidation product from the saponified part and setting freethe acids from the latter.

7. A process for recovering substantially th g entire saponifiable partof an oxidation product, obtainable by the liquid-phase oxidation offrom liquid to solid, non-aromatic hydrocarbons, in

i the form of fatty acids, which comprises subjecting the entireoxidationproduct to a saponiflcation process at temperatures of fromabout 280 C. to about 300 C. by means of an alkaline reacting agentselected. from the group consisting of the oxides, hydroxides andcarbonates of the alkali metals and alkaline earth metals while removingthe water and separating the unsaponi-- flablepart or the oxidationproduct from the sapon ified part.

8. A process of recovering substantially the entire saponiflable part ofan oxidation product, ob-. tainable by the liquid-phase oxidation offrom liquid to solid, non-aromatic hydrocarbons, in the form of fattyacids, which comprises subjecting the entire oxidation product to asaponiflcation process at temperatures of from about 280 C, to about 300C. by means of an alkaline reacting agent selected from the groupconsisting of the oxides, hydroxides and carbonates of the alkali metalsand alkaline earth metals, substantially in the absence of water,separating the unsanoniflable part or the oxidation product from thesaponifled part and setting tree the acids from the latter.

9. A process for comprises subjecting. oxidized material comprisingthe'saponiiiabl part of an oxidation product,

' obtainable by the liquid-phase oxidation of from part and setting free7 11. A process'forrecovering substantially the.

- oxidation product,

recovering fatty acids, which liquid to solid, non-aromatic hydrocarbonsto a saponification process at temperatures of. from about 280 C. toabout300 'C. by meansof an alkaline reacting'agent selected from thegroup consisting of the oxides, hydroxides and carbonates of the ,alkalimetals and alkaline earth metals, substantially in the absence ofwaterand setting free the acids from the latter.

10. A process for recovering substantially the entire saponifiable partof an oxidation product, obtainable by the liquid-phase oxidation orfrom liquid to solid, non-aromatic hydrocarbons, in the form of fattyacids, which comprises subiec :ing the entire oxidation product to asapomflcatemperatures of from about 280 C. to about 300 C. by means ofan alkaline reacting agent selected from the group consisting of theoxides, hydroxides and carbonates of the alkali metals and alkalineearth metals, whileremoving thewater, separating the unsaponifiable partof the oxidation product from the saponifled the acids from the latter.

tion process at entire saponiflable part of an oxidation product,

obtainable by the liquid-phase oxidation of from liquid to solid,non-aromatic hydrocarbons, in the form of fatty acids, which comprisessubjecting the entire oxidation product to a saponification 4 processat'temperatures ot from about 280, to ,about' 300 C. by means orannalkaline reacting agent selected from the group consisting of theoxides, hydroxides and carbonates of the alkali metals and alkalineearth metals in arflamount by about 3 to 8 percent inexcess of thatcorrespondmg to the saponiflcation number or the entire substantially inthe absence of water, separating the unsaponiflable part of theoxidation product from the saponifled part an setting-free the acidsfrom the latter. HANS BHLER.

